While a strong starting rotation and consistent lineup are vital components to any Major League team's successful championship run, a hot bullpen can cover up a lot of sins. At the same time, a bullpen that is struggling as the playoffs hit could find themselves watching the World Series from their living rooms.
Which is why now is the time to take a look at the state of each potential playoff team's bullpen.
First, we'll examine how the National League bullpens stack up, using numbers from the last 30 days. All figures come from of the start of play on September 21.
| Team | SV | IP | K/9 | BB/9 | HR/9 | HR/FB | ERA | FIP | WAR |
|---|---|---|---|---|---|---|---|---|---|
| Rockies | 8 | 107 | 8.83 | 3.11 | 0.93 | 9.80% | 3.62 | 3.60 | 1.7 |
| Brewers | 11 | 96 | 11.16 | 2.81 | 1.13 | 17.40% | 2.91 | 3.40 | 1.6 |
| Phillies | 8 | 108 | 9.17 | 3.42 | 1.00 | 12.00% | 3.67 | 3.84 | 1.2 |
| Diamondbacks | 12 | 76 | 8.64 | 3.79 | 0.83 | 10.90% | 4.03 | 3.89 | 0.9 |
| Marlins | 5 | 122.1 | 8.53 | 3.60 | 1.03 | 12.20% | 5.00 | 4.10 | 0.9 |
| Nationals | 10 | 86.2 | 6.96 | 2.18 | 0.93 | 8.20% | 3.43 | 3.86 | 0.8 |
| Pirates | 4 | 89.2 | 8.83 | 4.01 | 0.80 | 9.00% | 3.81 | 3.86 | 0.7 |
| Cubs | 6 | 89.1 | 10.48 | 4.53 | 1.11 | 12.50% | 5.04 | 4.04 | 0.7 |
| Dodgers | 6 | 106.2 | 10.80 | 3.88 | 1.43 | 19.50% | 5.32 | 4.24 | 0.6 |
| Cardinals | 5 | 83.1 | 9.50 | 2.59 | 1.3 | 13.50% | 3.89 | 4.00 | 0.5 |
Colorado Rockies
The Colorado Rockies have had the best bullpen over the last month according to fWAR. Even though they are slipping in the standings -- they hold just a one-game lead for the second wild card in the National League after Wednesday's action -- you can't blame the relievers, who have a National League-best 1.7 fWAR over that stretch. Their ERA of 3.62 is third-best in the league over that stretch.
These numbers come thanks in part to the addition of Pat Neshek, acquired at mid-season from the Philadelphia Phillies. The Rockies are getting great middle relief work from Scott Oberg and Chris Rusin as well, but closer Greg Holland has struggled a bit of late, with a 5.40 ERA in his last 10 innings. He and Jake McGee are key components of a 'pen that has a strikeout rate of 23.7% and ranks seventh-best in the National League, with an 8.4% walk rate that is fifth-best. If Holland and McGree do what they're capable of -- and if the Rockies hold on and make the postseason -- they could be a tough out in October.
Milwaukee Brewers
The Milwaukee Brewers are nipping at Colorado's heels for that final wild card spot, and they're doing it thanks to outstanding work by their relief corps. Their 1.6 team fWAR is second to Colorado over the last month, and they are the only team in the National League with a strikeout rate over 30% (31.1%) during that stretch. Opponents are hitting an National League-worst .190 against them, and their 7.8% walk-rate is third-best.
Brewers fans are a little miffed at closer Corey Knebel after he gave up 3 runs in the eighth and ninth innings on Wednesday night to blow a chance to move into a tie for first in the wild card, but that outing aside, he's been outstanding. Over the last 30 days, he still has an ERA of 2.19 and is striking out an insane 40.8% of hitters faced. Josh Hader has been even more ridiculous, whiffing more than half (51.0%) of all hitters during that same period. Anthony Swarzak, Jeremy Jeffress, and Oliver Drake have also pitched well in the second half, giving Milwaukee a collection of relievers that throw hard stuff and miss a lot of bats.
Arizona Diamondbacks
The Arizona Diamondbacks follow with a team-wide 0.9 fWAR over the last 30 days, fourth-best in the National League. Interestingly, they've thrown the fewest innings (76.0) of any National League bullpen over the last month, a testament to their outstanding starting pitching. Their team-wide 4.03 ERA is eighth-best in the National League, but they've done a terrific job of avoiding the long ball, with the second-lowest home runs per nine innings (HR/9) over the last 30 days.
Fernando Rodney is getting it done in the closer's role, but it's fair to wonder how the 39-year-old will hold up in October. Archie Bradley is probably the team's best overall reliever, with a 0.69 ERA in his last 13.0 innings, and David Hernandez is the only other reliever to throw at least 10 innings over the last month. If Arizona is going to go deep into the postseason, they'll have a handful of relief pitchers they can count on, but probably don't have the depth of their competition.
Washington Nationals
A true disaster going into the All-Star break, Washington's 0.8 fWAR is sixth-best in the National League over the last month, thanks largely to the additions of Ryan Madson and Sean Doolittle, both of whom have been excellent since arriving in a trade deadline deal with the Oakland Athletics. Doolittle has been the team's closer, and over his last 12 innings has an ERA of 1.25. Madson has an ERA of 2.25 during that same stretch, and is striking out 30.0% of all batters while walking less than three percent.
Matt Albers, Brandon Kintzler and Joe Blanton have all been stellar, fixing what was perhaps the greatest single area of weakness for any National League contender at midseason. Washington's Achilles heel in the playoffs the last half-decade has been blowing leads late in games, and they hope Madson and Doolittle are the solutions for that particularly nasty problem.
Chicago Cubs
The Chicago Cubs have the best record in the National League since the All-Star break, but some of their lower-tier relievers have struggled. The bullpen's cumulative 5.04 ERA is 10th out of 15 National League teams, and their 11.5% walk-rate is third-highest during that time.
On the plus side, Wade Davis continues to do an excellent job in the closer's role, with a 0.90 ERA over his last 10 innings. And kudos to Carl Edwards, he of the 1.64 ERA over his last 11 innings. Pedro Strop has also mostly been effective, too, but there is a drop-off after that, so Chicago will need quality starting pitching in the postseason.
Los Angeles Dodgers
The Los Angeles Dodgers' struggles over the last few weeks have been well documented, and despite having a roster the size of a small country, they can't seem to get their bullpen in order. The relievers blew two games against the Phillies this week, and overall have a 5.32 ERA over the last 30 days, fourth-worst in the National League.
Yes, Kenley Jansen is a beast, and if last year is any indication, he can pitch multiple innings in the playoffs if need be. Tony Cingrani, Tony Watson (acquired in a midseason trade with the Pittsburgh Pirates) and Brandon Morrow have been fine, but the electric-armed Pedro Baez has been brutal (11.74 ERA in his last 7.2 innings), and Josh Ravin and Ross Stripling have struggled, too. With questions in the starting rotation and a sputtering offense which has resulted in a 5-15 record this month, it might be a quick October for the once-mighty Dodgers.
St. Louis Cardinals
The St. Louis Cardinals are hanging in the wild card race, 2.5 games out, but despite an fWAR of 0.5 that is below the Dodgers' 0.6, their ERA of 3.89 is actually a run and a half better than L.A.'s, proof that WAR for relief pitchers in a limited sample size is a clunky stat.
The Cardinals' problem is they have no closer. Juan Nicasio has been excellent since a September trade with the Philadelphia Phillies, but he's ineligible to pitch in the postseason. Tyler Lyons has a couple of saves, but over the last 30 days, the St. Louis 'pen has just 5 saves total. The team is putting Adam Wainwright in the bullpen following his stint on the disabled list, and he could perhaps serve as the de facto closer for the next couple weeks and into October, should the Cardinals sneak into the postseason. But of all the teams on this list, St. Louis has the most unsettled relieving corps.